/*- * Copyright (c) 2013 The NetBSD Foundation, Inc. * All rights reserved. * * This code is derived from software contributed to The NetBSD Foundation * by Matt Thomas of 3am Software Foundry. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. */ #include <machine/asm.h> RCSID("$NetBSD: memcpy_neon.S,v 1.4 2026/03/11 21:54:21 andvar Exp $") .text ENTRY(memcpy) teq r2, #0 /* 0 length? */ cmpne r0, r1 /* if not, does src == dst? */ RETc(eq) /* yes, (to either) return */ mov r3, r0 /* keep r0 unchanged */ #if 0 cmp r2, #16 /* copy less than 8 bytes? */ bhs .Ldst_aligner /* nope, do it the long way */ 1: ldrb ip, [r1], #1 /* load a byte from src */ subs r2, r2, #1 /* and more to transfer? */ strb ip, [r3], #1 /* save it to dst */ bne 1b /* yes, do next byte */ RET /* return */ #endif .Ldst_aligner: tst r3, #7 /* is dst pointer word aligned? */ beq .Lsrc_aligner /* yes, check src pointer */ /* * Until the dst pointer is word aligned, read src and dst byte by * byte until it is aligned or we've copied everything. */ ldrb ip, [r1], #1 /* load a byte from src */ strb ip, [r3], #1 /* save the byte to dst */ subs r2, r2, #1 /* end of transfer? */ bne .Ldst_aligner /* no, try next byte */ RET /* yes, we're done! */ .Lsrc_aligner: push {r4-r5} /* save some registers */ add r4, r2, r3 /* keep a pointer to the end of src */ ands r5, r1, #7 /* get misalignment of src pointer */ beq .Lcongruent_main /* aligned, do it the fast way */ vdup.8 d1, r5 /* set offset for table */ rsb r5, r5, #8 /* calculate leftover of each word */ bic r1, r1, #7 /* dword align src pointer */ vldr d0, .Ltbl_value /* load table value */ vadd.u8 d0, d0, d1 /* add offset to it */ vld1.64 {d1}, [r1:64]! /* load a dword from src */ cmp r2, r5 /* do we already have enough? */ bhi .Lincongruent /* no, so read more */ .Lincongruent_finish: vtbl.8 d0, {d1-d2}, d0 /* merge last dwords */ cmp r2, #8 /* room for a full dword? */ #ifdef __ARMEB__ vrev64.32 d0, d0 /* word swap to LE */ #endif blo .Lfinish /* no, write final partial dword */ vst1.32 {d0}, [r3:64] /* yes, write final full dword */ b .Ldone /* and we're done! */ .Lincongruent: vld1.64 {d2}, [r1:64]! /* load a dword */ cmp r2, #8 /* can we write a full dword? */ blo .Lincongruent_finish /* no, finish it. */ vtbl.8 d1, {d1-d2}, d0 /* reorder */ vst1.64 {d1}, [r3:64]! /* store a dword */ subs r2, r2, #8 /* have we written everything? */ beq .Ldone /* yes, we're done! */ vmov d1, d2 /* prepare for next dword */ tst r3, #63 /* are we 64-byte aligned? */ bne .Lincongruent /* no, load next dword */ /* * We are now 64-byte aligned so all writes should fill one or more * cachelines. Even if d1 has 7 bytes cached, to write 32 bytes we * still need to read 4 dwords (3 full dwords and 1 dword for that * last byte). */ cmp r2, #32 /* can we write 4 more dwords? */ blo .Lincongruent_dword /* no, handle dword by dword */ vld1.64 {d2-d5}, [r1:64]! /* read 4 dwords */ cmp r2, #64 /* can we write 4 more dwords? */ blo .Lincongruent_4dword /* no, handle it */ 1: vld1.64 {d7-d10}, [r1:64]! /* read 4 dwords */ vtbl.8 d1, {d1-d2}, d0 /* reorder */ vtbl.8 d2, {d2-d3}, d0 /* reorder */ vtbl.8 d3, {d3-d4}, d0 /* reorder */ vtbl.8 d4, {d4-d5}, d0 /* reorder */ vst1.64 {d1-d4}, [r3:64]! /* write 4 dwords */ vmov d6, d5 /* move out of the way the load */ cmp r2, #96 /* have 8+4 dwords to write? */ blo 2f /* no more data, skip the load */ vld1.64 {d2-d5}, [r1:64]! /* more data, load 4 dwords */ 2: vtbl.8 d6, {d6-d7}, d0 /* reorder */ vtbl.8 d7, {d7-d8}, d0 /* reorder */ vtbl.8 d8, {d8-d9}, d0 /* reorder */ vtbl.8 d9, {d9-d10}, d0 /* reorder */ vst1.64 {d6-d9}, [r3:64]! /* write 4 dwords */ subs r2, r2, #64 beq .Ldone vmov d1, d10 cmp r2, #64 bhs 1b /* * we have leftovers in d1 and new untranslated date in d2-d5. */ .Lincongruent_4dword: cmp r2, #32 blo .Lincongruent_dword vtbl.8 d1, {d1-d2}, d0 /* reorder */ vtbl.8 d2, {d2-d3}, d0 /* reorder */ vtbl.8 d3, {d3-d4}, d0 /* reorder */ vtbl.8 d4, {d4-d5}, d0 /* reorder */ vst1.64 {d1-d4}, [r3:64]! /* write 4 dwords */ vmov d1, d5 /* move leftovers */ subs r2, r2, #32 beq .Ldone .Lincongruent_dword: #if 0 cmp r2, r5 /* enough in leftovers? */ bls .Lincongruent_finish /* yes, finish it. */ vld1.64 {d2}, [r1:64]! /* load a dword */ cmp r2, #8 /* can we write a full dword? */ blo .Lincongruent_finish /* no, finish it. */ vtbl.8 d1, {d1-d2}, d0 /* reorder */ vst1.64 {d1}, [r3:64]! /* store a dword */ subs r2, r2, #8 /* have we written everything? */ beq .Ldone /* yes, we're done! */ b .Lincongruent_dword /* and go get it */ #else cmp r2, r5 /* are the bytes we have enough? */ bls .Lincongruent_finish /* yes, finish it. */ mov ip, r2 /* get remaining count */ bic ip, ip, #7 /* truncate to a dword */ rsb ip, ip, #32 /* subtract from 32 */ ands r2, r2, #7 /* count mod 8 */ add pc, pc, ip, lsl #1 /* and jump! */ nop vld1.64 {d2}, [r1:64]! /* load a dword */ vtbl.8 d1, {d1-d2}, d0 /* reorder */ vst1.64 {d1}, [r3:64]! /* store a dword */ vmov d1, d2 /* prepare for next dword */ vld1.64 {d2}, [r1:64]! /* load a dword */ vtbl.8 d1, {d1-d2}, d0 /* reorder */ vst1.64 {d1}, [r3:64]! /* store a dword */ vmov d1, d2 /* prepare for next dword */ vld1.64 {d2}, [r1:64]! /* load a dword */ vtbl.8 d1, {d1-d2}, d0 /* reorder */ vst1.64 {d1}, [r3:64]! /* store a dword */ vmov d1, d2 /* prepare for next dword */ vld1.64 {d2}, [r1:64]! /* load a dword */ vtbl.8 d1, {d1-d2}, d0 /* reorder */ vst1.64 {d1}, [r3:64]! /* store a dword */ vmov d1, d2 /* prepare for next dword */ beq .Ldone vld1.64 {d2}, [r1:64]! /* load a dword */ b .Lincongruent_finish /* write last partial dword */ #endif .Lcongruent_main: vld1.32 {d0}, [r1:64]! /* load next dword */ cmp r2, #8 /* compare current ptr against end */ blo .Lfinish /* greater so write final dword */ vst1.32 {d0}, [r3:64]! /* store dword */ subs r2, r2, #8 /* compare current ptr against end */ beq .Ldone /* equal? we're done! */ tst r3, #63 /* have we hit a 64-byte boundary? */ bne .Lcongruent_main /* no, write next word */ cmp r2, #64 /* can we write 4 dwords? */ blo .Lcongruent_loop /* no, this dword by dword */ vldm r1!, {d0-d7} /* load next 7 dwords */ cmp r2, #128 /* can we write 16 dwords */ blo 3f /* no, then deal with 8 dwords */ /* * The following writes two 64-byte interleaving stores and loads. */ 1: vldm r1!, {d8-d15} /* load next 8 dwords */ vstm r3!, {d0-d7} /* store 8 more dwords */ cmp r2, #192 /* can we write 16+8 dwords? */ blo 2f /* no, don't load the next 8 dwords */ vldm r1!, {d0-d7} /* yes, load next 8 dwords */ 2: vstm r3!, {d8-d15} /* store 8 more dwords */ sub r2, r2, #128 /* we just stored 16 (8+8) dwords */ beq .Ldone /* if 0, we're done! */ cmp r2, #128 /* can we write 16 dwords */ bhs 1b /* yes, do it again */ cmp r2, #64 /* have we loaded 8 dwords? */ blo .Lcongruent_loop /* no, proceed to do it dword */ /* * We now have 8 dwords we can write in d0-d7. */ 3: vstm r3!, {d0-d7} /* store 8 more dwords */ subs r2, r2, #64 /* we wrote 8 dwords */ beq .Ldone /* if 0, we're done! */ .Lcongruent_loop: vld1.32 {d0}, [r1]! /* load dword from src */ cmp r2, #8 /* can we write a full dword? */ blo .Lfinish /* no, write last partial dword */ .Lcongruent_loop_start: vst1.32 {d0}, [r3]! /* store dword into dst */ subs r2, r2, #8 /* subtract it from length */ beq .Ldone /* if 0, we're done! */ vld1.32 {d0}, [r1]! /* load dword from src */ cmp r2, #8 /* can we write a full dword? */ bhs .Lcongruent_loop_start /* yes, so do it */ .Lfinish: vmov r4, r5, d0 /* get last dword from NEON */ tst r2, #4 /* do we have at least 4 bytes left? */ strne r4, [r3], #4 /* store the 1st word */ movne r4, r5 /* move 2nd word into place */ tst r2, #2 /* do we have at least 2 bytes left? */ #ifdef __ARMEB__ movne r4, r4, ror #16 /* yes, swap halfwords */ #endif strneh r4, [r3], #2 /* yes, store the halfword */ #ifdef __ARMEL__ movne r4, r4, lsr #16 /* yes, discard just written bytes */ #endif tst r2, #1 /* do we have a final byte? */ #ifdef __ARMEB__ movne r4, r4, lsr #24 /* yes, move MSB to LSB */ #endif strneb r4, [r3], #1 /* yes, store it */ .Ldone: pop {r4-r5} /* restore registers */ RET .p2align 3 .Ltbl_value: #ifdef __ARMEL__ .quad 0x0706050403020100 #else .quad 0x0001020304050607 #endif END(memcpy)
